[Modify] Replace it

websocket-sharp/Server/WebSocketServer.cs

@@ -854,11 +854,19 @@ namespace WebSocketSharp.Server
     /// </param>
     public void Stop (ushort code, string reason)
     {
-      lock (_sync) {
+      string msg;
-        var msg = _state.CheckIfAvailable (false, true, false) ??
+      if (!checkIfAvailable (false, true, false, false, out msg)) {
-                  WebSocket.CheckCloseParameters (code, reason, false);
+        _logger.Error (msg);
+        return;
+      }
 
-        if (msg != null) {
+      if (!WebSocket.CheckParametersForClose (code, reason, false, out msg)) {
+        _logger.Error (msg);
+        return;
+      }
+
+      lock (_sync) {
+        if (!checkIfAvailable (false, true, false, false, out msg)) {
           _logger.Error (msg);
           return;
         }
@@ -867,6 +875,7 @@ namespace WebSocketSharp.Server
       }
 
       stopReceiving (5000);
+
       if (code == (ushort) CloseStatusCode.NoStatus) {
         _services.Stop (new CloseEventArgs (), true, true);
       }